1. Field of the Invention
The present invention relates to a photosensitive material processing apparatus in which a photosensitive material is immersed in a processing solution stored in a processing tank.
2. Description of the Related Art
In a photosensitive material processing apparatus such as an automatic processor, a photosensitive material exposed imagewise is processed (developed or the like) with a processing solution by immersing the photosensitive material in a processing solution or spraying a surface of the photosensitive material with a processing solution while the photosensitive material is being conveyed.
In a presensitized plate (PS plate) processor which is an automatic processor for processing a photosensitive planographic printing plate (hereinafter referred to as a “presensitized (PS) plate”), that is, a photosensitive material in which a photosensitive layer is provided on a support such as an aluminum plate, in addition to a development process in which a PS plate exposed imagewise is immersed in a developer, a washing process in which a PS plate having been subjected to development processing is washed by blowing washing water against front and back surfaces of the PS plate, a desensitizing process in which desensitizing processing is carried out in such a manner that the front and back surfaces of the PS plate having been subject to washing processing are coated with a desensitizer such as a gum solution, and the like are provided.
In some of such PS plate processors as well, a heater is provided in a developer tank so that a developer in the developer tank is heated to a temperature in a temperature range in which PS plates are most suitably processed. At this time, in the PS plate processor, a developer in the developer tank is circulated and agitated by being sucked and jetted out from a spray pipe disposed in the developer by way of a circulating pump so that the temperature of developer in the developer tank becomes uniform.
In order that development processing for PS plates may be efficiently carried out so that the same product quality could be obtained, it is necessary to attempt liquid displacement in which a fresh developer is supplied to the surface of a PS plate conveyed in the developer and a fatigued developer is removed from vicinities of the surface of the PS plate.
However, there is a problem that reliable liquid displacement in the vicinities of the surface of the PS plate is difficult to carry out in a system in which a developer is simply made to jet out from a spray pipe disposed in a developer tank. Further, the developer flow is divided into upper and lower sides of a conveyance path by the PS plate conveyed in the developer tank, thereby making it difficult to control the temperature of the developer with high accuracy.
The present invention has been achieved in view of the aforementioned circumstances, and a first object of the present invention is to provide a photosensitive material processing apparatus in which, when a photosensitive material is processed by being immersed in a processing solution while the temperature of the processing solution is being adjusted, reliable liquid displacement in vicinities of the surface of the photosensitive material, and uniform temperature adjustment of the processing solution are made possible.
In the PS plate processor as described above, a conveyance path is formed using a guide plate and a PS plate is guided along the upper surface of the guide plate. Due to the guide plate being curved so that a surface thereof facing the conveyance path of the PS plate becomes concave, or the guide plate being formed by connecting a plurality of flat surfaces, a conveyance path having a downwardly convexed surface can be formed.
In the PS plate processor as well, it is necessary that a fresh developer may be supplied to front and back surfaces of the PS plate to allow uniform development processing for the PS plate. To that end, the guide plate is formed so as to have a through hole passing through from front to back surfaces thereof like punching metal, so as to allow a fresh developer at a lower side of the guide plate to be supplied to the side of the conveyance path of the PS plate.
However, when a through hole is formed on a guide plate with which the PS plate is brought into contact when the PS plate is moved, a corner at a widthwise-direction edge of the leading end of the PS plate tends to be pulled in the through hole, thereby causing damage to the PS plate (for example, bending) or transport deficiency.
The present invention has been achieved in view of the aforementioned circumstances, and a second object of the present invention is to provide a guide plate for conveying a photosensitive material, which prevents damage to a photosensitive material such as a printing plate and transport deficiency, which damage and transport deficiency are caused by a corner of the photosensitive material being pulled in a through hole when a conveyance path of the photosensitive material is formed.
In the PS plate processor as described above, a light receiving portion and a non-receiving portion are formed by exposure on a photosensitive layer, and thereafter, development processing is carried out by means of a developer. As a result, an unnecessary photosensitive layer is removed and an image is formed.
As for a photosensitive planographic printing plate, a so-called four-layer photopolymerization plate is used in which a photosensitive layer is formed on a support by a light adhesive layer, a photopolymerization layer or the like, and the surface of the printing plate is protected by an overcoat layer. This photopolymerization plate is heated to a predetermined temperature so that a photopolymerization layer of the light receiving portion is firmly adhered to a support via a light adhesive layer to improve printing resistance. Further, an overcoat layer which covers the photopolymerization layer is dissolved in water.
When the photopolymerization plate is subjected to development processing, a pre-heating process and a pre-washing process are provided before an automatic processor or prior to a developing process. The photopolymerization plate is heated prior to development processing, and thereafter, the surface of the photopolymerization plate is brushed while washing water is being supplied thereto, so that an overcoat layer removed. As a result, a photopolymerization layer of a non-receiving portion can be reliably removed at the time of development processing.
When such photopolymerization plates are subjected to development processing, an overcoat layer needs to be reliably removed prior to processing with a developer. To that end, in the pre-washing process, water is supplied from a spray pipe to the surface of the photopolymerization plate to swell the overcoat layer, and thereafter, the surface of the photopolymerization plate is brushed with a brush roller. As a result, the overcoat layer is swollen with and dissolved in washing water, and is easily peeled off.
The solubility and peeling property of the overcoat layer are greatly influenced by the period of time in which washing water adheres to the overcoat layer. The shorter this period of time, the worse the solubility and peeling property becomes. In the pre-washing process, it is necessary that brushing using a brush roller is carried out at least three seconds after water is supplied to the surface of the photopolymerization plate.
For this reason, there is proposed a structure in which a horizontal conveyance path of a photopolymerization plate is provided in the pre-washing process and washing water supplied from a spray pipe disposed immediately before a brush roller is jetted out toward the photopolymerization plate.
Although, in the pre-washing process carried out in the structure as described above, improvement in solubility and peeling property of the overcoat layer can be achieved in an intermediate portion of the photopolymerization plate in the conveying direction, washing water is apt to run down from ends of the photopolymerization plate in the conveying direction, particularly, a leading end thereof, and washing water cannot stay thereat for a required time. As a result, the solubility and peeling property of the overcoat layer are deteriorated. Further, washing water is apt to adhere unevenly to the ends of the photopolymerization plate and the overcoat layer is unevenly removed therefrom. As a result, when development processing of a photopolymerization plate is carried out, a remaining overcoat layer may cause a partial delay in development.
Such delay in development has a great influence on a finished state of a developed photopolymerization plate and may eventually be reflected in the quality of a printed matter obtained using this photopolymerization plate.
The present invention has been achieved in view of the aforementioned circumstances, and a third object of the present invention is to provide a preprocessing apparatus which prevents occurrence of processing unevenness caused by a partially remaining overcoat layer when pre-washing processing is carried out prior to development processing using a developer.
In the PS plate processor as described above, when a PS plate is conveyed, the PS plate is nipped by conveyance rollers (hereinafter referred to as a “conveyance roller pair”) which are disposed in a pair with a conveyance path of a PS plate interposed therebetween. The pair of conveyance rollers are rotatingly driven in a predetermined direction, whereby a conveying force is applied to the PS plate. Further, the conveyance roller pair are disposed at a downstream side of the processing process, whereby a processing solution used in the processing process is squeezed out from the surface of the PS plate.
As for a structure for imparting nipping force to the conveyance roller pair, various structures, for example, a structure in which a roller bearing for supporting a lower conveyance roller is held at a predetermined position and a roller bearing for supporting an upper conveyance roller is urged toward the bearing of the lower conveyance roller, can be used.
When processing for the PS plate is started in a state in which a predetermined nipping force is not imparted between the conveyance roller pair, transport deficiency of the PS plate may be caused. That is, when urging force between the conveyance roller pair disposed to face each other is not sufficient, when the PS plate is fed in between the conveyance roller pair, slippage occurs between the conveyance roller pair and the PS plate. As a result, there arises a problem that conveying force cannot be imparted to the PS plate.
Further, when the PS plate is nipped by the conveyance roller pair, it is necessary that a large nipping force may be imparted to squeeze out a processing solution adhering to the surface of the PS plate. For this reason, when the conveyance roller pair is removed/attached for the purpose of maintenance or the like, an operation resistible to a large urging force must be carried out. Such a troublesome operation of removing/attaching the conveyance roller pair complicates the maintenance of a PS plate processor.
The present invention has been achieved in view of the aforementioned circumstances, and a fourth object of the present invention is to provide a photosensitive material processing apparatus in which an operation of removing conveyance rollers disposed in a pair, or attaching the conveyance rollers so that the rollers are disposed in a pair is facilitated and a photosensitive material such as a PS plate can be processed with nipping force being properly imparted thereto between the conveyance roller pair.
In the PS plate processor as described above, processing performance of a processing solution stored in a processing tank is maintained in a range in which a PS plate can be properly finished, by replenishing a replenisher in accordance with a quantity of PS plates to be processed (processing replenishment) or by replenishing a replenisher in accordance with an elapsed time (age-based replenishment).
The PS plate processor is provided with a replenisher tank in which a replenisher is stored. The replenisher tank is provided so as to replenish a replenisher for a processing tank by operating a replenisher pump at a predetermined timing. Further, when a replenisher in the replenisher tank is reduced due to a replenisher being replenished for a processing tank, a fresh replenisher needs to be supplied to the replenisher tank.
The replenisher to be supplied to the replenisher tank is contained in a replenisher case. In the PS plate processor, a piping extending from the replenisher tank is connected to a cap provided in the replenisher case, and thereafter, the replenisher case is turned upside down to allow a replenisher to run down from the replenisher case to the replenisher tank.
However, when the replenisher case is turned upside down in a state in which the piping is connected thereto, breakage or unnatural bending occurs in the piping. As a result, there is a possibility that a replenisher may not reliably run down into the replenisher tank and may remain in the piping or replenisher case.
Further, the operation of mounting the replenisher case filled with the replenisher at a lower side of the apparatus while turning the replenisher case upside down is troublesome because an operator's working posture is not easy and this operation needs to be carried out at a high position.
The present invention has been achieved in view of the aforementioned circumstances, and a fifth object of the present invention is to provide a photosensitive material processing apparatus in which a replenisher case filled with a replenisher is easily mounted and a state in which a replenisher remains in a piping or replenisher case can be prevented.